M42 screw lens adapter, autofocus confirmation

I have a 135mm L/2.8 lens with a screw mount and a passive M42 to EOS adapter. Works great, except for the focusing challenge of course. I have the beep off anyway and I could just put the lens on and shoot with no setting changes (on my 40D).

If I get a M42 adapter with the focus chip, does that just make it beep with confirmation regardless, or does it only beep when there is actual focus? If the latter, how accurate is it?

The chipped adapters will beep the camera when in focus. I have one on my 500mm f/8 reflex lens, and it's quite accurate.

You might also consider an Ef-S screen to help you with the manual focus. Along with the AF confirmation beep, you should also see the plane of focus a lot better with the Ef-S screen.

Speaking from 5D usage - if you have the beep off, you have the beep off - only the focus point confirmation light will blip when you're in the focus range and (for me) only when you have the focus button depressed. As for the accuracy... I only have a 50/1.4 to go by, and... well, let's just say that it lets me know that I'm in the right neighborhood. YMMV.

ctham wrote in post #11131198
You might also consider an Ef-S screen to help you with the manual focus. Along with the AF confirmation beep, you should also see the plane of focus a lot better with the Ef-S screen.

This goes on the viewfinder?

The focusing screen is a separate thing, but it makes the plane of focus clearer in your viewfinder: https://photography-on-the.net/forum/showthre​ad.php?t=417029

I use very often a Zuiko 500mm F8 .. of course manual focus ..
And I don't imagine tu use an MF lens for action without AF confirm chip Euro TTL...

An then it' becomes really comfortable to use a MF lens for sport action ..
Just some samples

even in really dark conditions at 6400 isos with an F8 lens

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I just ordered a new generation ring from ebay.

And now for the lens buying madness ...

I've been interested in using a couple of my father's M42 lenses, and have a question regarding the adapters with confirmation chip.

You mentioned the 4th generation adapter. How do you know an adapter is "new" or what generation it is?

For example there were two M42 EOS adapters with confirmation chips on Fleabay this morning. One for $16, the other for $40. How do you know which is which? Price may not be an indicator of which generation the adapter is.

The main feature concerned with 4th gen chip is
"Another new feature is the "hard" blocking of shutter release until you get the confirmation signal. If you hold the shutter release when fully depressed, the shot will be taken immediately when you get the AF confirmation signal. This allows taking fast-moving subjects. "
You will probably have to buy a single chip and glue it to an M42 adapter

Already former programmable chip are mostly accurate to perform near to perfect AF confirm.

Many thanks for sharing your knowledge on these.

I see what you're referring to. That's a very interesting technology to incorporate into the adapter. I've noticed a couple that are describing programming the focal length, maximum aperture, and lens focus micro-adjustment as well. It appears that the technology has really advanced since the early aluminum screw adapters.

Would using a new generation adapter still be compatible with a split focus screen, or does the new focus confirmation chips render the split focus redundant?

I have no idea about the impact of the focus screen technology ..
I use an Af confirm chip with EG-S and EG-D without any trouble

The programability of the chip, FL and max aperture, doesn't really do much other than help you differentiate your lenses - it doesn't keep report an accurate f-stop for each shot.

Focus screen will not interfere with AF confirm chip functionality, or visa versa. Also, the AF confirm adapters that I've used, while admittedly inexpensive, haven't been able to lock in low light (ISO1600, f/2, 1/50) situations, so I've got a split screen on the way.

WhyFi wrote in post #11156566
Also, the AF confirm adapters that I've used, while admittedly inexpensive, haven't been able to lock in low light (ISO1600, f/2, 1/50) situations, so I've got a split screen on the way.

That's wrong in my case, I could lock 90% of the cases even at 6400 iso with a mirror lens at F8 for action or moving subjects
500mm F8 6400Iso 1/320

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newworld666 wrote in post #11159608
That's wrong in my case, I could lock 90% of the cases even at 6400 iso with a mirror lens at F8 for action or moving subjects
As you can see, even with a terrible AF body like a 5DMKII, it's working like a charm at very high isos ...
Based on my own experience, I would say, 3rd and 4th gen AF Confirm chip are really accurate and necessary for live candids or action with manual focus lenses ..

That's fantastic for you, but exactly why I prefaced my statement with, "in my case," and "admittedly inexpensive," (although they are supposedly, 'new generation' AF chips) no need to post the same images again and again and again.